According to the Federal Aviation Administration's Surveillance and Broadcast Service (FAA) their Surveillance and Broadcast Services Program was formed in 2005. That Program is charged with changing the nations air traffic control system from one that relies on radar technology to a system that uses precise location data from the global satellite network.
Enabling this evolution is a proven technology called Automatic Dependent Surfeillance-Broadcast (ADS-B). ADS-B is a crucial component of the nation's Next Generation Air Transportation System, and its implementation over the next 20 years will turn the next generation vision into a reality. After years of research and development, and use by general aviation pilots in Alaska and air transport carriers in the Ohio River Valley, the FAA determined in 2005 that ADS-B is ready to be made operational throughout the national airspace system.
With ADS-B, both pilots and controllers will see radar-like displays with highly accurate traffic data from satellites—displays that are updated in real time and don't degrade with distance or terrain. The system will also give pilots access to weather services, terrain maps and flight information services. The improved situational awareness will mean that pilots will be able to fly at safe distances from one another with less assistance from air traffic controllers.
The gains in safety, capacity and efficiency as a result of moving to a satellite-based system will enable the FAA to meet a tremendous growth in air traffic predicted in coming decades. Because ADS-B is a flexible and expandable platform, it can change and grow with the evolving aviation system.
Currently in Aircraft Broadcast there are four digit assigned transponder codes and pressure altitude whenever they are pinged by ground-based radar from air traffic control. In many busier air spaces the information on position and altitude as well as whether the airplane is level, climbing or descending, is broadcast from the ground so that it can be viewed inside aircraft with the appropriate equipment available on most medium and larger aircraft. It is presently believed that some planes can also interpret the Mode S transponder signals from other aircraft so that they can display traffic information even when not receiving the information broadcast from the ground. With respect to wind information there are currently subscription services that will send forecast winds to the plane. A pilot can thus scroll through these and get a graphical representation of the forecast winds at square grid points at 3,000-feet intervals. It is also a fact that many aircraft are presently equipped with Mode S transponders.
The FAA has mandated that all aircraft at some point in the future comply with ADS-B. This protocol involves broadcasting position information from the plane's GPS. Presumably any plane able to send this information out would also be able to interpret this information coming in from other planes. This will mean that air traffic control and other planes will not need the ground-based radar to know the position of aircraft in their vicinity.
Most larger aircraft “know” what their winds are. Looking at a certain page on the GPS or flight management system (FMS) will show that the winds might be out of the west at 50 knots, represented as “270/50.”
A turbulence instrument can also provide two numbers as measures of frequency and intensity of vibrations. The accelerometer could consist of a damped weight attached to a spring and a measuring device. The unit could send out a signal saying that it was experiencing 45 vibrations/minute at an intensity of “3”, which might correspond to 1.4 times the force of gravity.
This information could be appended to an ADS-B transmission. The ADS-B signal would likely consist of tagged information in a certain order that would end with something like <end of data> or an equivalent tag. It could be followed by a <comments> or a supplemental section that, after sending the required position and altitude information, could send “winds:270/50, turb:45/3.”
Alternatively, this information could be sent to ground or satellite receivers and relayed to other aircraft capable of receiving those signals.
Once this data has been received in an aircraft, a more basic display could simply append the wind and turbulence data onto the traffic altitude reading. For example, most traffic displays would show another aircraft, 7,000 ft higher as a little diamond with “+70” written above it. If that plane were in smooth air that was blowing from the northwest at 30 knots the display might read “+70 315/30 00-0.
More complex instrumentation could combine actual wind information (or forecast wind information) with known aircraft performance data to predict what the ground speed and fuel burn would be at different altitudes. This could be accessed through different pages in the flight management system or it could be sent to alert the pilots when a clearly superior altitude option is available.
Under the proposed system the crew of one aircraft can look at the screen which previously provided only a graphical representation of traffic but now in addition to the usual altitude information next to each aircraft symbol there is also information on that plane's winds and the condition of its ride. The pilot in another plane is thus alerted by a message on one of his cockpit screens that a particular altitude would give him a better speed and cause the flight to burn less fuel. A pilot in a third plane checks a particular information screen and sees that going up 2,000 feet would save him fuel over all but might lengthen the time of the flight while going down 4,000 feet would get him to his destination minutes faster but cause him to burn more or less fuel.